Gas turbine engines include compressor blades that rotate to compress inlet gases and turbine blades that rotate to harness energy from expansion of outlet gases. Gas turbine engine blades are attached to gas turbine engine disks. The gas turbine engine disks rotate with the gas turbine engine blades and may experience peak stresses in excess of about 1000 megapascals (MPa) due to centrifugal loading from the gas turbine engine blades and weight of the gas turbine engine disks themselves.
In some examples, gas turbine engine disks may not be directly exposed to the flow path of hot gases in the gas turbine engine. Thus, in some implementations, maximum surface temperatures of the gas turbine engine disks may be about 650° C. The thermal and mechanical stresses to which the gas turbine engine disks are exposed impose design criteria which the alloys that form the gas turbine engine disks may satisfy. These design criteria include relatively high yield strength and tensile strength to inhibit yield and fracture of the gas turbine disk, relatively high ductility and fracture toughness to impart tolerance to defects, relatively high resistance to initiation of fatigue cracks, and relatively low fatigue crack propagation rates. In some implementations, gas turbine disks may be formed from nickel (Ni)-based superalloys, which may satisfy at least some of these design criteria.
In some examples, gas turbine engines may include some components formed from alloys and some components formed from ceramics or ceramic matrix composites (CMCs). The alloy components and ceramic or CMC composites may contact each other.